Systems exist that use onboard cameras to monitor the surroundings of a vehicle as an auxiliary means for checking safety when a vehicle is driven. For example, in the monitoring system disclosed in Kokai Patent Application No. 2002-19556, plural onboard cameras are arranged on the periphery of the vehicle, and the images captured by the onboard cameras are reshaped and synthesized to generate an image that shows the state of a vehicle's surroundings viewed from above the vehicle. The image obtained is displayed on a monitor.